The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 14, 1999
Filed:
Aug. 29, 1997
Garry Gillette, San Jose, CA (US);
Credence Systems Corporation, Fremont, CA (US);
Abstract
A load circuit for an integrated circuit tester provides an adjustable load at a terminal of an integrated circuit device under test (DUT) when the DUT is generating an output signal at the terminal. The load circuit includes positive and negative current sources for producing positive and negative currents of magnitudes that are non-linear functions input reference voltages. A diode quad connects the negative current source to the DUT terminal when the DUT output signal is below an input threshold voltage and connects the positive current source to the DUT terminal when the DUT output signal is above the threshold voltage. The current sources provide a non-linear, exponential, transfer function between input reference voltage and output current magnitude so that the current sources provide a relatively wide output current range in response to a relatively narrow input reference voltage range.